The GTR score is calculated using data from GPX file. The data includes total distance, total net finish time, total elevation gain and loss and elevation profile. In addition calculation is using GAP model defined by Strava. Based on 6 million running samples GAP (Grade Adjusted Pace) model is implemented into GoodTrail score calculation. The model was researched and build by Drew Robb from Strava Engineering.
This model is not perfect. It does not take into account any trail variable trail conditions such as mud, snow, ice or other ground conditions.
The good thing is the model will give the same score result for the same GPX file. No matter who will be runnning with you or how many people will run the same trail.
The score result is not dependent on the results of other runners.

You can disconnect anytime. Just revoke access for the GoodTrail app in your Strava My Apps settings.

Several sources were analyzed to find the most optimal GAP model that covers different types of trail running elevation profiles, elevation gain and loss. Here are the sources used to build the model:
- An Improved GAP Model
- Individualization matters: the gradient adjusted pace model of Kilian Jornet
- Data Science, Music and Sports. Part 1: Data Collection - Hypothesis Testing
- Minetti, A. E. et al. (2002). Energy cost of walking and running at extreme uphill and downhill slopes. Journal of Applied Physiology 93, 1039–1046.
- Improving Grade Adjusted Pace
- Grade Adjusted Pace (GAP)

Mountain running or trail running is an incredibly exciting form of activity that is gaining more and more popularity among sports enthusiasts. Running on mountain trails offers not only amazing views and the opportunity to commune with nature but also numerous health benefits. Participating in running competitions in the mountains is great fun and an excellent way to test your abilities. For those seeking even greater challenges, ultra marathon running on mountain trails is a true test of endurance and determination. Besides the sporting aspect, mountain running allows for exploring picturesque corners and discovering previously unknown places, further enriching this unique experience. Regular mountain running improves physical fitness, strengthens muscles and the cardiovascular system, and reduces stress, bringing health benefits on many levels.